Let's break this down. We're going to add 4200 and 2122 together.

Step 1: We'll start by adding the digits 0 & 2 in column 1 and get 2.

Step 2: We'll start by adding the digits 0 & 2 in column 2 and get 2.

Step 3: We'll start by adding the digits 2 & 1 in column 3 and get 3.

Step 4: We'll start by adding the digits 4 & 2 in column 4 and get 6.

So, 4200 + 2122 = 6322.

